A while ago, YouTube launched a simple demo of an HTML5-based video player. Recently, we published a blog post on our pre-spring cleaning effort and your number one request was that YouTube do more with HTML5. Today, we're introducing an experimental version of an HTML5-supported player.
HTML5 is a new web standard that is gaining popularity rapidly and adds many new features to your web experience. Most notably for YouTube users, HTML5 includes support for video and audio playback. This means that users with an HTML5 compatible browser, and support for the proper audio and video codecs can watch a video without needing to download a browser plugin.
Our support for HTML5 is an early experiment, and there are some limitations. HTML5 on YouTube doesn't support videos with ads, captions, or annotations and it requires a browser that supports both the video tag and h.264 encoded video (currently that means Chrome, Safari, and ChromeFrame on Internet Explorer). We will be expanding the capabilities of the player in the future, so get ready for new and improved versions in the months to come.
To try it out, go to the HTML5 page via TestTube or visit this page and join the experiment. This will enable HTML5 video for your browser, provided that it's one of the browsers mentioned above and fits in with the parameters we already referenced. (If you've opted in to other experiments, you may not get the HTML5 player.) You can also enable Feather watch (visit http://www.youtube.com/feather_beta) along with HTML5 video for an even simpler, faster YouTube experience.
We are very excited about HTML5 as an open standard and want to be part of moving HTML5 forward on the web.
Source:http://youtube-global.blogspot.com/